Concrete roller-tamper



Jan. 28, 1964 sc JR 3,119,314

CONCRETE ROLLER-TAMPER Filed May 51, 1960 2 Sheets-Sheet l GOTTUEB SCH/E1. //e.

INVENTOR.

BY MM G. SCHIEL, JR

CONCRETE ROLLER-TAMPER Jan. 28, 1964 2 Sheets-Sheet 2 Filed May 31, 1960 INVENTOR.

.Y J M M R m w s M w MP @Y B United States Patent Ofitice 3,119,314 Patented Jan. 28, 1964 CUNCRETE RGLLER-TAMPER Gottlieb Schiel, Jan, 44% Alum Rock Ave, San Jose 27, Calif.

Filed l /lay 31, l tl, Ser. No. 33,009 4 Claims. (Cl. 9450) The present invention is a continuation-in-part of my prior application Serial Number 793,609, filed February 16, 1959, and now abandoned; and relates to a new process of finishing concrete and to tools for use in such new process. In more particular, the invention involves a new process of achieving by mechanical means a submergence of the aggregate, a plurality of interruptions, substantially spaced in time, of the natural setting of the surface portion, and compactions of such portion of a recently poured, unset, concrete slab, and the construction of devices for accomplishing such interruptions and compactions.

It is known that in hot weather, a concrete slab sets more rapidly than in colder weather, and that such accelerated setting results in cracks in the concrete, particularly in the formation of surface cracks, that is shallow cracks, and spawling. It has been found that if the top of the slab to a depth of a quarter to a half inch is disturbed slightly two of three times before final setting that such cracks do not appear. This disturbance may be considered to effect a release of shrinkage tensions as the chemical process of setting takes place. The release of such tensions prevents the later formation of cracks in the concrete. Also, it is possible that this prevention of surface cracking prevents cracking of the deeper portions of the slab as a crack is never initiated, and uneven drying, or setting, caused by and at a crack, never takes place.

In the prior art of finishing cement slabs, it has been the practice to press into the surface of the slab a screen for the purpose of submerging the larger pieces of the aggregate. This leaves only sand, cement, and water at the top of the slab. The depth to which the coarse aggregate was submerged varied, but generally was in excess of a quarter of an inch. In general such screen was held rigid by a rectangular frame which had secured thereto upright handles so that a man could walk on the newly poured slab and, working close to his feet, raise the screen above the slab and then force it down into the top portion of the slab. The screen, frame, and handles is called a tamper, and its use called tamping, or jitter bugging.

Walking on, or, more properly, in a freshly poured concrete slab is arduous work for a finisher, and often detrimental to the final quality of the slab, but a smooth surface could not be given the slab unless the above tamping operation was performed. This tamping had to be done long before the slab became stiff, nearly set, and before the bull-floating, and final troweling and brushing. Once the slab began to set, it was too late to tamp as the marks of the temp and its operators feet could not be smoothed out. Further, a tamper in the hands of any but the most skilled, resulted in uneven results, the tamper was not forced far enough or too far into the top of the slab, the imprints of the screen either overlapped unnecessarily or not enough, and the work varied as the operator moved about on the slab. Also, in spite of spraying the slab to prevent rapid evaporation of water therefrom, and the application of various seals and covers, surface cracks, all too often, developed.

Also, in the prior art there are rollers of various designs which have been intended for use in the tamping of concrete slabs. However, such rollers have not found acceptance in the industry for various reasons pertinent to each of these prior art devices. Generally, the prior rollers have lacked suitable means on the surfaces thereof for submerging the concrete aggregate gravel and for being self cleaning.

Having in mind the above difficulties and defects of the prior art devices and their uses in the tamping and finishing of the surfaces of concrete slabs, it is an object of the present invention to provide devices for use in the submergence of coarse concrete aggregate, tamping, and the compaction of the slab surface in the slab finishing process so as to prevent or greatly reduce the formation of surface cracks therein.

it is a further object of the present invention to provide a concrete tamper which in use impresses a flat wire belt in rolling imprint on a slab.

Another object of the present invention is the performance of a concrete slab finishing process made possible by the use of the herein described device, a process involving submergence of coarse aggregate prior to setting, or stiffening, of the slab, and a compacting of the slab surface, just prior to troweling, with the device of the present invention.

A still further object of the invention is that of devising a tamper that operates by rolling on a concrete slab, which tamper is to have a cylindrical rotatable drum with a fiat wire screen, or belt, wrapped around its face.

Still another object is that of devising a tamper that employs two parallel spaced apart cylindrical faced drums adapted to roll on a concrete slab and to have therebetween and wrapped therearound and in contact with the faces thereof an endless flat wire belt.

A device which will be useful in performing such new process, which obviates the defects of the prior art tampers, and which achieves the aforementioned objects, comprises: a right cylindrical tube with closed ends; wrapped around the cylindrical surface of such tube, a fiat wire belt, or screen; and a long handle for rolling the tube, or roller; which handle has at its end adjacent the roller a bow, the ends of which are secured to the cylinder ends by means of pins and bearings which allow the cylinder to roll, or rotate, on its longitudinal axis with respect to the handle.

Two forms of tampers made in accordance with the above outline are hereinafter described in detail and illustrated in the accompanying drawings, in which:

PEGURE l is a plan view of such tamper.

FIGURE 2 is an end elevational view of the tamper of FIGURE 1.

FEGURE 3 is an enlarged view in perspective of a portion of the flat-wire screen covering the cylindrical surface of the tamper shown in the other figures.

FEGURE 4 is a perspective view showing a modification of the invention.

FTGURE 5 is a view similar to FIGURE 3 but showing the screen from a different point of view.

The first disclosed embodiment, that of FIGURES 1, 2, and 3, has two main portions, the handle portion 11 and the roller portion 12. The roller is in the form of a right cylindrical closed-end drum 13. It has been found that the drum may be small in diameter and very light in weight for most concrete finishing. A drum having about a seven inch diameter, a length of forty inches, and a weight of about sixteen pounds is satisfactory. Each drum end 14 may be flush or slightly recessed with respect to an end edge of the cylindrical portion thereof. Axially of each drum endis secured a journal pin 16, or trunnion, about which the drum will roll and to which trunnions the handle 11 is fitted. The face of the drum is covered with a flat wire foraminous belt 17. This belt is made of flat strips 18 of steel with one edge of each strip against the face of the drum. The strips are about three eighths inch wide and about one sixteenth inch thick. Each strip is bent sinuously as shown and extends parallel with the axis of the drum. The strips interfit as shown and are so held to each other by a wire rod 19 passing thru the interfitting portions of adjacent strips and parallel to the extension of such strips. The openings thru the belt formed by the bending of the strips is about one half by one inch. The belt is of standard manufacture and readily available. Belts of this form may be had in other sizes both as to opening and as to the dimensions of the strip, but the dimensions given have proven satisfactory in the use of the device. The belt is loose enough so that it may creep circumferentially of the drum but should be held from axial movement by one or more retainer pins 21 secured to the face of the drum at each edge thereof so as to bear against the side edges of the belt. The circumference of the drum is such that the belt snugly fits the drum with the belt having all of its openings of the same dimensions. The drum and belt will Weigh about thirty pounds.

The handle portion 11 is divided into two parts, a shaft 22, or pole, and a yoke, or bow. The yoke is generally Y-shapcd in form, with the free end of each of its arms 23, 24 carrying or formed with a bearing 25 adapted to receive one of the axles 16 of the drum. One end of the pole 22 is secured in a socket 26 by suitable means such as winged clamping screws 27 threaded thru the sides of the socket, and the socket is secured medially of the yoke arms so as to constitute the stem of the Yshaped form. The pole and its socket extend substntially normal to the axis of the drum. The socket is made so that the pole is easily removed therefrom so that transportation and storage of the roller is simplified and so that the roller may be used with handles of various lengths as may be desirable when various size concrete slabs are Worked. A wood pole about two inches in diameter and ten to twenty feet long, is satisfactory for the shaft 22 of the roller on most concrete slab jobs. With the pole removed, ropes may be used for pulling the roller across very wide slabs.

By making the handle pole 22 easily separable or attachable with respect to its yoke 23, .24 and the roller portion '12, the portability of the device is greatly enhanced. The roller is ready for use in a few moments, when brought ,to a job, by inserting the proper end of the pole in its socket 26 and tightening the wing screws 27 against that portion of the pole received therein.

The tamper is brought into use after a slab has been poured and brought to screed grade, and has partially set, or stiffened. This time varies and is dependent on several factors, quality of mix, temperature, thickness 01f slab, slope, etc. There is no [need for the finisher to enter on the slab. V-lith the right length handle shaft 22, he can push or pull the roller 12 to and over any portion of the slab. Where there are obstructions in the way of working from the outside of the slab, it may be necessary to get out on it, but such travel on the slab is greatly reduced as compared with the use of the prior vertically reciprocated tampers. The present roller tamper is rolled back and forth across the slab, the finisher using the handle to accomplish this rolling. The flat wire belt rolls and sinks into the concrete. The drum stays on top of the concrete and uniformly over the slab, limits the penetration of the belt in the slab. There is very little, if any, pushing, or moving about, of the unset concrete by the passage over it of the roller. The weight of the roller is kept low for this reason, as well as that of making it easy to handle at all times. The sinking of the belt into the concrete submerges the coarse aggregate in the concrete well below the surface of the slab and to a uniform depth. This, in the language of the finisher, brings the fat to the surface, gets the coarse aggregate out of the way of the finishing process, and compacts the top of the slab so that a harder and denser surface 4 may be had by the final trowling than would be possible without tamping.

The use of the present invention in the finishing of a slab, has resulted in a radical departure in the process of finishing a slab. The slab may be tamped sooner and later than had been possible, practical, or useful with the prior vertical tamping. If a slab is tamped vertically before it has partially set, the action of the tamper walking in the concrete undoes much of the effect of the tamping. The coarse aggregate does not stay down well below the slab surface and its submergence is not to a uniform depth. If the tarnping is done too late, as the slab becomes very stiff, the foot marks of the tamper operator weakens the slab strength. There is no heavy load applied to the slab, no tramping of feet on or in the concrete, and no stirring or unwanted agitation thereof in the use of the present invention. Further, the roller does the job in a fifth, or less, of the time required by previous methods. Thus, the tamping can be done just when needed over the whole slab. With the prior methods, they started too soon and finished too late. Another new effect is the compaction of the surface of the slab and the prevention of cracks therein. This is done by a second, or even a third, rolling of the slab with the present device just before troweling. The final rolling of the slab compacts the surface, breaks-up incipient cracks, prevents cracks, and for a too dry slab surface, brings water and fat to the surface so that it may trowled. Thus, applicant has devised a concrete slab finishing process that involves tamping the slab a plurality of times with a rolling motion and by use of a roller having a ribbed, grid, or patterned surface with the circumferential area of the projections small with respect to the circumferential area of the depressions.

The fact that the belt is separate from the drum, and that the flat wire strips can and do move with respect to each other and the drum, breaks the dried cement therefrom, and keeps the drum and belt clean.

The second disclosed embodiment of the invention, that of FIGURES 4 and 5, differs from the first disclosure, principally, in that it embodies a roller assembly 30 comprising two right cylindrical closed-end drums 31, 32 which are held in parallel spaced apart position with respect to each other by reach rods 33, one on each side of the device.

Around and between the drums, coextensive with the axial length of the drums, and contacting a semi-cylindrical area of each drums cylindrical shell 34, is an endless flat wire belt 17 of the same construction as that previously described. Each drum end 37 has secured thereto and axially of the drum a trunnion 38 which is journaled in an end of a reach rod 33. Each of the drum ends 37 is slightly larger in diameter than the shell 34 to provide flanges 39 which prevent the belt from creeping off the ends of the drums.

The roller assembly 30, composed as above described, is provided with a handle portion 41 which has as parts thereof a long pole 42, or shaft, which has its end adjacent the roller assembly 3i rigidly secured to a bow, or yoke, having arms 43, 44. Each end of the yoke is forked with a reach rod 33 in such fork. Thru the sides 46 of each fork and thru the reach rod in such fork and medially of the length thereof, is placed a pin 47 for the purpose of pivotally securing the handle portion 41 to the roller assembly. Each of the yoke arms is encompassed with a rotable sleeve 48 in opposition to an edge of the belt with the axis of such sleeve normal to the run of the belt adjacent such sleeve. These sleeves may at times contact the belt edge to aid in maintaining the belt in proper alignment on the drums.

Applicant has found that satisfactory dimensions for a roller assembly as above described are four inch diameter drums made of 20 gage sheet. The drums may be 30 to 40 inches in axial length and spaced on 12 inch centers. The belt Wire width and thickness. and

the belt openings may be the same as previously described for FIGURE 3. Of course, the Width of the belt should conform to the axial length of the drums.

FIGURE 5 is a perspective view of a section of a belt such as is intended for use on either the device of FIG- URES 1 and 2 or that of FIGURE 4. The difference in the views of FIGURES 3 and 5 is in the aspect from which the belt is viewed. The direction of belt curve in FIGURE 5 conforms to that found in FIGURE 4. The reference numerals in FIGURE 5 are the same as in FIGURE 3 and refer to the same parts.

The double roller tamper of FIGURE 4 operates in much the same manner as the single roller of FIGURES 1 and 2. The double roller tracks better than the single roller but is more difi'icult to operate in confined spaces. Due to the use of smaller drums in the double roller modification, the wall thickness of these smaller drums may be considerably less than that of the single drum of FIGURES 1 and 2 so that the total Weight of the roller assembly of FIGURE 4 may be considerably less than that of the roller assembly of the single drum of FIGURES 1 and 2.

Having thus described the construction and use of two forms of my invention, I claim:

1. A concrete tamper, comprising: a drum having an imperforate cylindrical surface, a fiat wire articulated belt composed of a plurality of fiat wires bent and arranged to give said belt a grid-like form, adjacent wires having pivotal means connecting said adjacent wires together for pivotal movement with respect to each other, said belt having extended surfaces formed by the edges of said wires, one of said belt surfaces being arranged in extended peripheral contact with said drum surface with the flat wires of said belt extending axially of said drum, said belt being separate from said drum whereby said wires may have movement relative to said drum, and handle means attached to said drum so that said belt and drum may be moved thereby in rolling contact with an unset concrete slab to submerge aggregate therein.

2. The combination of claim 1 in which all of said wires are of the same thickness, width, and length.

3. The combination of claim 1 in which said drum has closed ends.

4. A concrete tamper, comprising: two cylindrical closedend drums having imperforate cylindrical surfaces, a trunnion secured to each drum end coaxial of said drum, reach rods receiving said trunnions and holding said drums in parallel spaced apart relationship, a fiat wire articulated belt composed of a plurality of flat wires bent and arranged to give said belt a grid-like form, adjacent wires having pivotal means connecting said adjacent wires together for pivotal movement with respect to each other, said belt having extended surfaces formed by the edges of said wires, said belt being endless and arranged around and between said drums so that one of said belt surfaces is in extended peripheral contact with said drums surfaces with the flat Wires of said belt extending axially of said drums, and handle means attached to said reach bars whereby said belt and drums may be moved in rolling contact with an unset concrete slab to submerge aggregate therein.

References (Cited in the file of this patent UNITED STATES PATENTS 1,190,948 Peterson July 11, 1916 1,560,295 Keeler 1. Nov. 3, 1925 1,560,734 Rook Nov. 10, 1925 1,626,879 Shidler et al. May 3, 1927 1,674,833 MacChesney June 26, 1928 1,839,000 Phan-Quang Dec. 29, 1931 2,258,205 Halvorson Oct. 7, 1941 2,587,406 Talbert Feb. 26, 1952 2,975,684 Humphrey Mar. 21, 1961 FOREIGN PATENTS 214,508 Great Britain Apr. 24, 1924 

1. A CONCRETE TAMPER, COMPRISING: A DRUM HAVING AN IMPERFORATE CYLINDRICAL SURFACE, A FLAT WIRE ARTICULATED BELT COMPOSED OF A PLURALITY OF FLAT WIRES BENT AND ARRANGED TO GIVE SAID BELT A GRID-LIKE FORM, ADJACENT WIRES HAVING PIVOTAL MEANS CONNECTING SAID ADJACENT WIRES TOGETHER FOR PIVOTAL MOVEMENT WITH RESPECT TO EACH OTHER, SAID BELT HAVING EXTENDED SURFACES FORMED BY THE EDGES OF SAID WIRES, ONE OF SAID BELT SURFACES BEING ARRANGED IN EXTENDED PERIPHERAL CONTACT WITH SAID DRUM SURFACE WITH THE FLAT WIRES OF SAID BELT EXTENDING AXIALLY OF SAID DRUM, SAID BELT BEING SEPARATE FROM SAID DRUM WHEREBY SAID WIRES MAY HAVE MOVEMENT RELATIVE TO SAID DRUM, AND HANDLE MEANS ATTACHED TO SAID DRUM SO THAT SAID BELT AND DRUM MAY BE MOVED THEREBY IN ROLLING CONTACT WITH AN UNSET CONCRETE SLAB TO SUBMERGE AGGREGATE THEREIN. 